Redundancy and high availability at the application level
In this type of solution, only application data are replicated. And only the application is restared in case of failure.
With this solution, restart scripts must be written to restart the application. This solution is platform agnostic and works with applications inside physical machines, virtual machines, in the Cloud. Any hypervisor is supported (VMware, Hyper-V...).
Examples
- Video management: Milestone (Management, SQL, Log, Event)/SafeKit
- Video management: Genetec (SQL)/SafeKit
- Access control: Nedap (AEOS, SQL)/SafeKit
- New application (restart scripts to write): Windows, Linux
Redundancy and high availability at the virtual machine level
In this type of solution, the VMS software is put inside a virtual machine. The full Virtual Machine (VM) is replicated and restarted (Application + OS).
The advantage of this solution is that there is no restart scripts to write per application. This solution is generic for any VMS software. It works with Windows/Hyper-V and Linux/KVM but not with VMware. This is an active/active solution with several virtual machines replicated and restarted between two nodes.
Examples
- Building management: Siemens Desigo CC/SafeKit
- Video management and access control: Siemens Siveillance suite/SafeKit
- New application (no restart script to write): Windows/Hyper-V, Linux/KVM
- Asynchronous replication => data loss
- Manual failover (no automatic failover)
- Not a high availability solution
- Requires a shared disk
- Price of the shared disk and its installation (SAN, iSCSI)
- Configuration complexity of Windows failover cluster (AD…)
- Remote sites = replicated storage
- Simple and economical
- Synchronous replication => no data loss
- Automatic failover and failback
- No shared disk
- Free trial and quick installation guide
